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Macktech689

Big Dog
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About Macktech689

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    BMT Veteran VIP

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    Male
  • Location
    North Carolina

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  1. Macktech689

    exhaust valve lash

    When I first read this post I cringed, it's so easy to bend and break the valve train parts if you don't adjust that engine exactly right. Won't be the first time!
  2. Macktech689

    presure in coolent tank

    The most likely cause of a MP-8 pushing coolant is the EGR cooler or injector sleeves. The first step is to perform a combustion leak test on the surge tank, if the test fluid turns green combustion gas is present in the cooling system. Check the cooler first by removing the hose and elbow and looking for coolant or chunks of soot in the cooler outlet. If your cooler looks OK you should get the sleeves replaced. I have never seen a head gasket failure on these engines. If the test fluid stays blue check your air drier for coolant.
  3. Macktech689

    Mack TRLR AUX

    The TRLR AUX switch operates the center pin hot system. It is used to supply 12V to the trailer center pin only when the key is off. It is used by gasoline tanker trucks to operate the over fill protection devices on the trailer when loading. The switch will not power the center pin with the key on or parking brake released. When the key is on the center pin is powered all the time to operate trailer ABS systems.
  4. Macktech689

    Turbo Actuator

    Replacing the actuator requires use of premium tech tool software. PTT has always had a operation to install and calibrate the actuator, if you put it on without doing it right the malfunction light will stay on and the turbo won't perform properly. You're dealer will have to do it, takes less than half an hour.
  5. Macktech689

    No throttle .Please help.

    Keep in mind any loss of voltage or ground to the control modules will log 6-4 also. The fault isn't always in the data link wiring. Fixed a 6-4 fault this week that was caused by engine harness wires rubbing on the block causing the engine module to lose power.
  6. Macktech689

    Diagnostics

    Blink code 6-4 is caused by a loss of communication between control modules on the J1939 data link.
  7. Macktech689

    Truck won't start 08 Granite

    Replace fuse F7 in the BEC.
  8. Macktech689

    Ground relay

    That is a circuit breaker that protects against system damage it there is a battery short to ground. Personally I would not bypass it.
  9. Macktech689

    A/C not working

    Fuse 41 is in the EPDM outside on the firewall, it's a mini fuse, right side 3rd from the top. Marked fan clutch 15a. If that is the fuse with no power, it comes off power relay #3 inside the cab behind the glove box area.
  10. Macktech689

    A/C not working

    Voltage to the APADS also comes from fuse 41 ( 15a ) down the red wire, but before it gets there it runs through the Freon high pressure switch connector. Also check the APADS ground.
  11. Macktech689

    2004 mack ch fan need help!!

    The only way to remove the password is to flash and program the control module.
  12. Macktech689

    Mac cxu613 fan clutch

    The easiest way to check to see if the fan is capable of engaging is to disconnect it from the engine harness and run the engine over 1000 rpm. The fan should fully engage in around 10 seconds, if it doesn't replace the fan drive. Loss of voltage triggers a limp home mode, keep in mind the fan drive will rarely fully engage during normal operation 75 to 80% is normal.
  13. Macktech689

    Mp8 code

    The only thing I get from what you posted is it a engine fault, you'll need to hook up with diagnostic software to get a better fault code description.
  14. Macktech689

    Bull gear on mp8 engines

    There was no change to the flywheel housing when the staked idler gears were installed, removing the housing is no small job the back and bottom of the engine needs to come off. You can check the idler gear through the PTO cover at the top of the housing on the right side to see if it is loose, if it is you will also see where it's rubbing on the housing. The video you mentioned may have been of a MP-7. A good picture of the top of the housing would be helpful, a pic of the bottom won't show anything.
  15. Macktech689

    Mp7 2007 04 EPA Harness

    The harness for that engine runs in the $600 range I think, I don't buy them I replace them. I've replaced dozens of engine harnesses, it's not a bad job as far as I'm concerned. The worst part of the job on a 04 emission's MP-7 is getting the harness disconnected from the mass flow tube module behind the alternator bracket.

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